The most common and most likely answer to this crossword clue is the 5 plus 4 letter word DRESS CODE
I've seen this crossword clue in The Daily Telegraph
D
R
E
S
S
C
O
D
E
More clues leading to the result DRESS CODE
- Line up before Morse? It tells us what we should assume
- Add seasoning to fish – European, posh restaurant might insist on this
- What to wear to finish convention
- Acceptable habit?
- Set of rules for some who are buttoned up?
- Set of rules which may mean men are ‘tied’?
- In this German town, mostly doctors go around in black tie!
- Don Corleone started with a song — a matter of habit, perhaps
- Crossed blue denims and embroidered tops could be informal
- Possibly informal convention for grooming
Buddy explains!
The straight part
We know that "Acceptable habit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case acceptable habit = dress code.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.